Generally automobiles are equipped with a steering lock device which is disposed in a vicinity of a steering column and operable in conjunction with a key switch of a cylinder lock type for operating an ignition switch. The steering lock device is constituted such that when a rotor of the cylinder lock is rotated to a “LOCK” position and thereafter the key is pulled out from the cylinder, the device causes a lock pin to project into a recess formed in a steering shaft to thereby prevent rotation of the steering shaft and the steering wheel.
In such a steering lock device, if the cylinder body is in any way detached from a housing secured to the steering column, an operation cam for the lock pin connected to the rotor may become accessible from outside so that the steering lock can be unlocked without using the key. Therefore, it was necessary to prevent the cylinder body from being pulled out easily.
In order to achieve the end, Japanese Patent Application Laid-Open Publication (kokai) No. 8-104202, for example, has proposed to prevent the cam for moving the lock pin from rotating in an unlocking direction when the cylinder body is detached from the housing.
In the above prior art device, however, a control lcver adapted to move in the pulling-out direction of the cylinder body and a prevention member for engaging a cam shaft, etc. have a relatively complicated structure, which makes the assembly thereof harder to carry out.